1. Field of the Invention
The present invention relates to an air conditioning machine having indoor and outdoor units, and more particularly to an improvement of the heat exchangers provided in the indoor and outdoor units.
2. Description of the Related Art
An air conditioner in general comprises an indoor unit positioned in a room to be air-conditioned and an outdoor unit positioned outdoors, which are connected to each other via refrigerant tubes and electrical wires.
Since users' demands for a decrease in the size and space required for these units has been increasing, manufacturers must increase the heat exchanging performance of an air conditioner, while satisfying the user's demand.
For this purpose, for example, a middle portion of the heat exchanger in the vertical direction of an indoor unit is bent at an obtuse angle and protruded outward, so that the heat exchange area is maintained, while the height of the heat exchanger is reduced, thereby reducing the height of the unit body.
The indoor unit comprises an air blowing fan for taking air in the room into the unit body, causing the air to flow through the heat exchanger, subjecting the air to heat exchange, and blowing the heat-exchanged air back into the room. A cross flow fan is selected as the air blowing fan in view of its property.
The length of the cross flow fan in its axial direction is substantially the same as the width of the heat exchanger. The cross flow fan comprises circular end plates, partitioning plates arranged at intervals, and a number of blades arranged along the circumferential end portions of the partitioning plates. The cross section of the cross flow fan is substantially circular.
In order to suppress the size of the unit body to as small as possible, the diameter of the cross flow fan is set to as small a size as possible, while still being capable of providing the necessary amount of air.
In the above heat exchanger, the cross flow fan is arranged at the back of the bent portion. Depending on the position of the bent portion, at least one of the upper and lower ends of the heat exchanger is spaced apart far from the cross flow fan.
The heat-exchanged air is not sufficiently introduced to portions apart from the heat exchanger, resulting in inconsistencies in heat exchange efficiency in different portions.
Jpn. UM Appln. KOKAI Publication No. 4-68921 discloses a heat exchanger having an improved structure to overcome the above problem.
As shown in FIG. 16, a heat exchanger H is divided into three parts, so that an upper portion forms an acute angle (an inverted v shape), and a front portion is bent at an obtuse angle and protruded outward. A fan F is arranged in the heat exchanger H.
With this heat exchanger H, the height thereof can be reduced as compared with a heat exchanger in which only the middle portion is bent. In addition, since the upper and lower end portions of the heat exchanger can be positioned near the fan F, the heat exchange efficiency can be improved.
However, in a front portion Ha of the heat exchanger H corresponding to a front inlet port a, through which the greatest amount of air is introduced, since the middle portion of the heat exchanger is bent at an obtuse angle and protruded outward as in the conventional heat exchanger described above, the distances (La to Ld) between the back surface of the front portion Ha and the circumferential surface of the fan F differ greatly from each other.
As a result, in that portion of the heat exchanger H corresponding to a front inlet port a, through which the greatest amount of air is introduced, the air inlet pressure is liable to vary, resulting in a lack of uniformity in the amount of inlet air.
In addition, since the fan F generates a rustling sound when blowing air, a silent operation cannot be achieved. Moreover, since the amount of inlet air is not uniform, the heat exchange efficiency improves very little. Further improvement of the heat exchanger is required.